a.TestConcatExample.java Source code

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Here is the source code for a.TestConcatExample.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package a;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hdfs.MiniDFSCluster;
import org.apache.hadoop.hdfs.web.WebHdfsFileSystem;
import org.apache.hadoop.hdfs.web.WebHdfsTestUtil;
import org.junit.Test;

import java.io.IOException;
import java.net.URISyntaxException;
import java.util.Random;

import static org.junit.Assert.assertEquals;

public class TestConcatExample {
    Random r = new Random();

    @Test
    public void concatIsPermissive() throws IOException, URISyntaxException {
        MiniDFSCluster cluster = null;
        final Configuration conf = WebHdfsTestUtil.createConf();
        conf.set("dfs.namenode.fs-limits.min-block-size", "1000"); // Allow tiny blocks for the test
        try {
            cluster = new MiniDFSCluster.Builder(conf).numDataNodes(2).build();
            cluster.waitActive();
            final FileSystem webHdfs = WebHdfsTestUtil.getWebHdfsFileSystem(conf, WebHdfsFileSystem.SCHEME);
            final FileSystem dfs = cluster.getFileSystem();

            final FileSystem fs = dfs; // WebHDFS has a bug in getLocatedBlocks

            Path root = new Path("/dir");
            fs.mkdirs(root);

            short origRep = 3;
            short secondRep = (short) (origRep - 1);
            Path f1 = new Path("/dir/f1");
            long size1 = writeFile(fs, f1, /* blocksize */ 4096, origRep, 5);
            long f1NumBlocks = fs.getFileBlockLocations(f1, 0, size1).length;
            assertEquals(5, f1NumBlocks);

            Path f2 = new Path("/dir/f2");
            long size2 = writeFile(fs, f2, /* blocksize (must divide 512 for checksum) */ 4096 - 512, secondRep, 4);
            long f2NumBlocks = fs.getFileBlockLocations(f2, 0, size2).length;
            assertEquals(5, f2NumBlocks);

            fs.concat(f1, new Path[] { f2 });
            FileStatus[] fileStatuses = fs.listStatus(root);

            // Only one file should remain
            assertEquals(1, fileStatuses.length);
            FileStatus fileStatus = fileStatuses[0];

            // And it should be named after the first file
            assertEquals("f1", fileStatus.getPath().getName());

            // The entire file takes the replication of the first argument
            assertEquals(origRep, fileStatus.getReplication());

            // As expected, the new concated file is the length of both the previous files
            assertEquals(size1 + size2, fileStatus.getLen());

            // And we should have the same number of blocks
            assertEquals(f1NumBlocks + f2NumBlocks,
                    fs.getFileBlockLocations(fileStatus.getPath(), 0, size1 + size2).length);
        } finally {
            if (cluster != null) {
                cluster.shutdown();
            }

        }
    }

    private long writeFile(FileSystem fs, Path p, int blockSize, short replication, int numBlocks)
            throws IOException {

        int bufferSize = 4096;
        FSDataOutputStream os = fs.create(p, true, bufferSize, replication, blockSize);

        int i = 0;

        byte[] data = new byte[bufferSize];
        r.nextBytes(data);
        while (i < blockSize * numBlocks) {
            os.write(data);
            i += data.length;
        }
        os.close();
        FileStatus fileStatus = fs.getFileStatus(p);
        long f1Len = fileStatus.getLen();

        assertEquals(i, f1Len);

        return f1Len;
    }
}